This invention relates to the medical instruments for extracorporeal treatment of blood and user interfaces for such instruments. One embodiment of the invention relates to a user interface for medical instruments for Renal Replacement Therapy and Artificial Kidney therapies.
1. Renal Replacement Therapies
Renal Replacement Therapy (RRT) can be performed in specialized dialysis centers for treatment of chronic patients that have permanently lost kidney function and in hospitals for treatment of patients with a need for temporary replacement of renal function. Different modalities of Continuous Renal Replacement Therapy (CRRT) have been used to treat patients suffering from excess fluid overload and acute renal failure. In acute settings, CRRT has been performed using standard methods of hemodialysis and continuous arterio-venous hemofiltration (CAVH). More recently, continuous veno-venous hemofiltration (CVVH) has been used to reduce the complications associated with such issues as hemodynamic instability and need for arterial access. Regardless of the type of medical equipment used and the specific type of treatment performed, RRT requires establishing an extracorporeal blood circulation path that passes blood through a filtration device.
RRT performs two primary blood treatment functions: ultrafiltration (removal of water from blood plasma), and solute clearance (removal of different molecular weight substances from blood plasma). RRT involves the use of a filter in a blood circuit through which circulates extracorporeal blood temporarily withdrawn from a patient. The RRT filter, also called hemofilter or dialyzer, can be set up to perform either or both of these functions simultaneously, with or without fluid replacement, accounting for the various modes of renal replacement therapy. xe2x80x9cClearancexe2x80x9d is a term that describes the removal of substances, both normal and waste product, from blood.
Ultrafiltration is the convective transfer of fluid out of a plasma compartment of a filter and through pores in the filter membrane. The pores of the filter membrane pass (filter) water, electrolytes and small and middle-sized molecules (up to 20,000 to 30,000 daltons) from the blood plasma. Large molecules, proteins blood cells and other large-sized plasma components (as well as a portion of the water and smaller components) do not pass through the filter membrane and remain in the plasma compartment of the blood circuit and are returned to the patient. The ultrafiltrate output (e.g., water extracted from the blood) from the filtration pores is similar to plasma, but without the plasma proteins or cellular components. Since the concentration of small solutes is the same in the ultrafiltrate as in the plasma, no clearance is obtained from the plasma, but fluid volume, e.g., water, is removed.
Dialysis is the diffusive transfer of small solutes out of a blood plasma compartment of a filter by diffusion across the filter membrane. This transfer occurs as a result of a concentration gradient, with diffusion occurring from the filter compartment with higher concentration (typically the blood compartment) to the filter compartment with lower concentration (typically the dialysate compartment). Since the concentration of solutes in the plasma decreases, clearance is obtained, but fluid may not be removed in dialysis. Ultrafiltration can be combined with dialysis to obtain both clearance and fluid removal from blood plasma.
Hemofiltration is the combination of ultrafiltration and fluid replacement in the treatment of blood. Typically, hemofiltration treating larger volumes of blood than is needed for fluid control. The replacement fluid contains electrolytes, but not other small molecules. Since the net effect of replacing fluid without small solutes and ultrafiltration of fluid with small solutes results in net removal of small solutes, clearance is obtained during hemofiltration.
2. Limitations of User Interface of Existing Devices for RRT
RRT devices use sets of disposable blood passage circuits (generally referred to as xe2x80x9cdisposablesxe2x80x9d) generally including tubing, filters, catheters, sensors and connectors that form a fluid circuit and are in direct contact with the blood and the fluid removed from the blood. These disposables can be assembled from components made by various manufacturers. Some more expensive disposables such as dialyzers can be used several times to treat the same patient. In some cases, disposable sets come assembled and the user need only mount the disposable blood passage on an instrument and pumping machine, and then prime the blood passage with sterile saline solution prior to its use. When the RRT device is ready for use, it is connected to the network of disposable and fluid filled tubes and electronic sensors that include the disposable blood passageway.
Modern RRT devices are microprocessor controlled. The microprocessor operates pumps, reads sensors and communicates with the user via a user interface regarding the RRT treatment. In more advanced RRT devices, the user interface has a graphics display that may be a touch screen or have an associated keypad. By interacting with a display and keys, the user interface enables a user to control the RRT device and monitor its operation.
During the operation, the RRT device detects conditions that trigger alarms and require user intervention. These alarms may occur often. For example, joints between parts in the blood passage disposable can spring leaks, allowing the ingress of air and facilitating clotting. Clotting of blood often occludes the blood passages. These RRT devices incorporate pressure sensors that enable them to detect disconnection and occlusion of tubing and components of the blood circuit. Air and blood leak detectors are also used to detect other alarm conditions that require immediate action from the user.
To operate RRT devices, a high degree of skill is required from users to troubleshoot the causes of alarms and promptly rectify the condition that provoked the alarm. A quick response from the user is needed because the RRT device is usually stopped as a result of the alarm, and within minutes the blood in the circuit may coagulate. Generally, when an alarm condition occurs, a user will receive an alarm notification and an alarm code from the RRT device. For example, code xe2x80x9cE001xe2x80x9d may be displayed on a numeric display. The user will interpret this as an alarm code by remembering that xe2x80x9cE001xe2x80x9d is a particular alarm or by consulting a manual for the RRT device that defines the display codes for the device. In the latest generation of RRT machines, less cryptic text messages are presented that describe alarm conditions. Instead of flashing an alarm code E001, for example, the RRT device displays a message such as xe2x80x9cInfusion Tubing Disconnectedxe2x80x9d. This plain language alarm message methodology is effective, but is still not intuitive to less-trained operators of the RRT device. Also, in the global marketplace, confusion often results from a language barrier and non-English speaking operators have difficulty with English language messages.
U.S. Pat. No. 5,858,239 discloses a dialysis machine that has a graphics display where a user is assisted by simple pictograms similar to xe2x80x9ciconsxe2x80x9d used by the commonly used Microsoft Windows(trademark) personal computer operating system. Another user interface that makes use of graphical icons instead of or complimenting text messages is disclosed in U.S. Pat. No. 5,620,608 for a dialysis machine. Although these icons help a user of a dialysis device navigate through a menu system, they are not helpful in troubleshooting faults in the blood fluid path of the device. A graphics user interface for an aphaeresis blood processing apparatus using pictorials is disclosed in U.S. Pat. No. 5,653,887, which displays icons and a symbolic diagram of the apparatus with an arrow pointing towards an element (blood centrifuge) requiring user attention. However, the graphics user interfaces disclosed in the prior art lack the ability to clearly direct a user to the specific point in the blood fluid path where an occlusion has been detected or the blood flow continuity has been broken.
A new and improved graphical user interface (GUI) for a RRT machine has been developed that integrates pictograms that point the user to the exact location of a fault in the machine blood circuit or fluid path.
The GUI addresses the needs of fluid removal and dialysis users by providing an intuitive interface that includes a dynamic pictorial diagram of the RRT device. The diagram shows the device in outline form, and emphasizes the fluid path, e.g., series of disposable components through which various fluids flow during treatment. In RRT devices these fluids include the pathway for the patient""s blood, and can additionally include fluid paths for ultrafiltrate, dialysate and replacement solution.
The GUI as disclosed here is directed to an RRT device, but can be used in assisting any treatment that involves extracorporeal circulation. Extracorporeal blood circulation involves the continuous withdrawal of blood from a patient, where the blood is processed outside of the patient and then returned to the patient. Examples of such treatments are blood aphaeresis, heart-lung machines, full or partial heart bypass and transfusion of blood.
The pictorial diagram of the fluid path on the GUI display is designed to primarily assist the operator of an RRT device in identifying the source of an alarm caused by a malfunction of the circuit. The GUI display also may be used to assist the operator in assembling the disposable blood circuit, mounting it on the RRT pumping device, threading the tubing of the circuit into roller pumps, and connecting sensors and de-bubbling components of blood passage to the RRT device.
The pictorial aid of the GUI shows various interconnected tubes, valves, pumps and sensors of the disposable extracorporeal circuit. Tube lines of different color can identify different fluids. For example, bloodlines made be red on the display, and dialysate lines yellow. During normal operation of the device, only the lines actively involved in a particular treatment will be displayed. For example, if a dialysate solution is not involved in a treatment (such as hemofiltration), the corresponding dialysate fluid lines will not be displayed. The direction of fluid flow may be indicated by arrows or by an animation of the displayed pictogram. The pump rotation and fluid motion can be animated on the display as can be the level of fluid in different reservoirs such as dialysate, replacement solution or effluent collection bags.
If a fault is detected by the RRT device at a particular point along the fluid path, the corresponding position of the fluid path as shown on the pictogram will be accentuated. The location of the fault can be a particular bloodline segment, a pump, a reservoir, a connector or a sensor. A sensor can be, for example, a pressure sensor, an air detector, a weight scale or a blood leak detector. The fluid path element that needs attention from user can be identified on the display by a change of color, flashing of a specific portion of the diagram or by changing shape of the displayed element. In addition, an arrow on the display can point to the element shown in the pictogram. Typically a message is displayed elsewhere on the graphics screen instructing the user how to rectify the problem. The pictogram is immediately responsive to user actions. For example, if a disconnected sensor symbol is being flashed to attract the user""s attention, and the user re-connects it, the pictogram will immediately change to its normal state.
Another aspect of the proposed method is that it assists the operator in detecting tubes that are not properly inserted into sensor elements of the RRT device console. Voltage outputs from sensors, such as a photometric blood leak detector and an ultrasonic air detector, can be used to detect fluid tubes that are not properly inserted into the sensor or other components of the RRT device. The user attention of the operator will be attracted by the flashing element of the pictogram so that user could insert the tube into the sensor tubing receptacle. The pictorial element will immediately stop flashing if the condition is corrected.